Putty knife



FIG. 1 is a perspective view of a putty knife showing our new design;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a left side elevational view thereof;

FIG. 4 is a top plan view thereof;

FIG. 5 is a bottom plan view thereof; and

FIG. 6 is an elevational view of an alternative embodiment thereof. 

The ornamental design for a putty knife, substantially as shown. 